Speed reducing mechanism



Jan. 15, 1935. v, ANDREWS SPEED REDUCING MECHANISM Filed Jan. 51, 1935 v INVENTOR 8 I L. 1 ANoREws BY L i g x 6 ATTOIIQ 4 Patented Jan. 15, 1935 UNITED STATES PATENT OFFICE SPEED REDUCING MECHANISM Application January 31, 1933, Serial No. 654,512

6 Claims.

This invention relates to speed-reducing mechanisms, and more particularly toa mechanism suitable for actuating a feed regulator for delivering coarse material at a uniform and adjustable rate to the inlet of a pulverizing apparatus.

It is one object of the invention to provide a speed-reducing mechanism which is simple and inexpensive to manufacture.

It is a further object of the invention to provide a speed-reducing mechanism which is compactand which is so arranged that the reduced speed may be easily adjusted over a wide range.

It is a further object of the invention to provide a speed-reducing mechanism for a feed regulator which may be driven from the shaft of a high speed pulverizer and yet the feed of material may be adjusted to a very low rate if desired.

With these and other objects in view, as will be apparent to those skilled in the art, the invention resides in the combination of parts set forth in the specification and covered by th claims appended hereto.

Referring to the drawing illustrating one embodiment of the invention, and in which like reference numerals indicate like parts, I

Fig. 1 is a vertical section through a feed regulator, the section being taken substantially on the line 11 of Fig. 3; V

Fig. 2 is a top plan View of the regulator, partially broken away for clearness of illustration;

Fig. 3 is a section on the line 33 of Fig. 1;

Fig. 4 is a perspective view of the feeding rate indicator;

Fig. 5 is an elevation of a portion of the apparatus, showing the indicator pointer and associated parts;

Fig. 6 is a detail of the worm gear and cam;

Fig. 7 is a perspective view of the oscillating lever;

Fig. 8 is a perspective view of the adjustable stop; and

Fig. 9 is a section on the line 9-9 of Fig. 1.

The embodiment illustrated comprises a horizontal rotatable circular table 12, and a hopper 13 mounted above the table and arranged to present material thereto. The hopper is provided with an opening 14 at one side, and a stationary knife or scraper 16 is mounted close to the upper surface of the table in a position to deflect material through this opening as the table rotates. The material which passes through the opening falls into an inclined chute 17 which may lead to a pulverizi'ng apparatus (not shown).

A rotatable agitator 18 is provided in the hopper 13 to prevent arching of the material and to compel the material to revolve with the table. Both the agitator and the table are mounted on the upper end of a vertical shaft 19. A glass window 21 is provided above the chute 1'7 so that the operator may view the falling stream of material.

The knife 16 is. preferably so arranged that it may be moved to an inoperative position and thus stop the feed of material even though the table continues to rotate. For this purpose the outer end of the knife is fixed to the lower end of a vertical pin or stud 22 (Fig. 2), and a lever arm 23 is fixed to the upper end of this stud. The stud is rotatably supported inthe hopper. The lever arm 23 is provided with a vertically slidable pin 24 which is arranged to enter the opening in either of two apertured bosses 25 and 26. When the pin engages the boss 25, as shown in Fig. 2, the knife will be in the feeding position, and when the pin engages the boss 26 the knife will be placed across the opening 14 so that no material will be deflected from the table.

A frame or bracket 28 is located beneath the table 12 to form a support for the hopper 13,- and a gearbox or casing 29 is connected to the lower end of the frame. The vertical shaft 19 is supported just beneath the table 12 by a bearing 30 on the frame 28. This bearing is lubricated by means of a grease cup 32. p The lower end of the shaft is supported in a sleeve bearing 33 in the gear box 29, and a roller thrust bearing 34 is provided beneath the shaft to receive the Weight of the rotating parts.

A worm gear wheel 36 is rotatably mounted on the shaft 19 directly above the bearing 33, and a cam 37 is provided on the upper face of the gear. This cam 3'7 is preferably formed by a circular plate eccentric with respect to the gear and fastened to the gear by means of screws 38. A horizontal worm 40 is rotatably supported in bearings 41 in the gear box 29 and meshes with the gear 36. One-end of the worm shaft extends outside of the gear boxes and carries a suitable driving pulley 42.

Above the gear 36 I provide a lever arm 4 which is arranged to lee-oscillated in a horizontal plane by means of the cam 37. In the preferred construction this lever arm is formed by an elongated horizontal plate having a transverse slot &5 in its central portion to receive the shaft 19' and two parallel ribs 46 (Fig; 7) on itslower face which engage opposite sides of the cam 37.

The ribs 46 extend lengthwise of the plate. A boss 48 is provided at one end of the plate, and this boss is bored to receive a vertical pin 49 (Fig. 3) which is mounted in the gear box and forms a pivotal support for the plate. The other end of the plate is provided with an upwardly projecting lug 50. The pin 49 is preferably located on the opposite side of the shaft 19 from the worm 40.

Above the lever arm 44 I provide a horizontal arm 52 arranged with one end in the path of the lug 50 and the other end connected to the shaft 19 by a one-way clutch mechanism. While various types of one-way clutches may be used for this purpose, I prefer to employ a clutch of the friction type. The particular clutch illustrated comprises a central pinion 53 (Fig. 9) to which the arm 52 is firmly keyed. This pinion is freely rotatable on the shaft 19. Surrounding the pinion is an annular cage 54 which carries three small cams 56 having teeth in mesh with the pinion. An annular housing 5'7 surrounds the cage 54, and the inner surface of the housing contacts with the cams. The parts are so arranged that if the pinion 53 is turned in a clockwise direction in Fig. 9, the housing will remain stationary. If the pinion is turned in a cormter-clockwise direction, the cams 56 will bind against the housing and cause the whole clutch to turn as a unit. In order to take up any lost motion in the clutch and ensure the desired operation, three helical tension springs 58 are provided, each extending between a stud 59 projecting radially from the pinion and a pin 60 on the cage 54. An oil cup 62 (Fig. 1) is provided on the housing 57 so that the interior of the clutch may be easily lubricated.

The clutch housing 5'7 is connected to the shaft 19, but the connection between these parts is preferably yieldable so that the driving mechanism will be protected in case the agitator or table should become blocked by a foreign body. For this purpose I provide a collar 63 which is keyed to the shaft just above the clutch housing. This collar is fastened to the housing by a small pin or bolt 64 which extends through laterally projecting flanges on the two parts. The pin 64 is arranged to shear if an unusually heavy load is applied thereto.

It will be noted that the lug 50 serves to move the arm 52 in one direction only, that is, in a counter-clockwise direction in Fig. 3. The arm is urged in the opposite direction by a spring 66 which in the embodiment illustrated is shown as a helical tension spring extending horizontally between a bolt 6'7 in the wall of the gear box and an arm 68 projecting from the arm 52 in a direction radial of the shaft 19. The arms 52 and 68 form an integral L-shaped member. The clockwise movement of this member is limited by an adjustable stop or abutment '70 located in the path of the arm 68. This stop '70 is formed from a rod of circular cross-section bent into the shape of an L, and welded or otherwise secured to a nut '71 mounted on a horizontal rotatable screw '72. The screw is provided with a handwheel '74 and is supported in a cover plate 75 fastened to the side of the gear box 29. Collars 76 are mounted on the screw to prevent endwise movement thereof. In order to prevent the nut '71 from turning with the screw I provide a bar '78 which is fastened to the cover plate '75 in a position parallel to the screw. This bar extends between the stop '70 and an overhanging portion '79 (Fig. 8) on the nut.

It is desirable to provide means for indicating to the operator the position of the nut '71. For this purpose I provide a follower 81 shown as a thin rectangular plate having a vertically elongated opening 82 therein. The width of this opening is equal to the diameter of the rod '70, and at assembly the rod extends through t.e opening. The lower end of the plate 81 is fastened to a horizontal shaft 83 which extends through the cover plate 75 and carries a pointer 84 on its outer end. Numerals 85 (Fig. 5) may be provided on the cover plate in the form of a circular are adjacent to the end of the pointer.

The operation of the invention will now be apparent from the above disclosure. The pulley 42 is rotated at a constant speed by any suitable source of power, preferably by means of a belt drive (not shown) from the shaft of the pulverizer with which the feeder is associated. This rotates the worm 40 which in turn drives the gear 36 and the cam 3'7 at a reduced speed. The cam 37 causes the lever 44 to oscillate about the pin 49. As the lever 44 swings to the left, the lug 50 will strike the arm 52 and turn the pinion 53 in a counter-clockwise direction. The earns 56 will instantly engage the clutch housing 5'7 and cause the entire clutch to turn as a unit. Since the clutch housing is connected to the shaft 19 by means of the pin 64 and the collar 63, the shaft will also turn, carrying with it the table 12 and the agitator 18. The movement of these parts will cause material in the hopper 13 to be deflected by the knife 16 into the chute 17. As the lever 44 swings back to the right, the spring 66 Will cause the arm 52 to swing to the right until its movement is checked by the stop 70 in the path of the arm 68. During this return movement the cams 56 will release their grip on the clutch housing 57, and the shaft 19 will be held stationary by the resistance of the material in contact with the table 12 and the agitator 18. By turning the handwheel '74, it is possible to move the stop '70 along the screw '72 and thus vary the extent of oscillation of the arm 52. This will vary the rate at which the table 12 is advanced and thus permit the rate of feed to be controlled. The adjustment can be made as fine as may be desirable, since the cams 56 in the one-way friction clutch will grip the clutch housing at any and all relative positions. The position of the nut '71 which controls the feeding rate is always indicated by the pointer 84.

The entire construction is simple, compact, and comparatively inexpensive. Because of the great speed reduction obtained by the cam, levers, and clutch, it is not necessary to use high ratio worm gearing. The worm 40 therefore can be and preferably is of the multiple-thread type, which is much more efficient than a single thread worm. The worm and worm gear may operate in an oil bath, which will also lubricate the other adjacent parts, including the lower bearings 33 and 34 of the shaft 19.

In the claims appended hereto I have for convenience used such expressions as vertical, horizontal, etc., in order to set forth the claimed structure more clearly. It is to be understood, however, that my improved speedreducing mechanism will operate in positions other than that illustrated, and that these expressions are not to be considered as limitations except in so far as they define the positions of the parts relative to each other.

Having thus described my invention, What I claim as new and .desire to secure by Letters Patent is:

1. A speed-reducing mechanism comprising a vertical shaft, an arm extending outwardly from the shaft, a one-way clutch mechanism connecting the arm with the shaft, an adjustable stop to limit the movement of the arm in one direction, a spring to move the arm toward the stop, a pivotally mounted lever to move the arm in the opposite direction, a gear rotatably supported on the shaft, a cam mounted on the gear and arranged to oscillate the lever, and means to rotate the gear.

2. A speed-reducing mechanism comprising a vertical shaft, an arm extending outwardly from the shaft, a one-way clutch mechanism connecting the arm with the shaft, an adjustable stop to limit the movement of the arm in one direction, a spring to move the arm toward the stop, a pivotally mounted lever to move the arm in the opposite direction, a worm gear rotatably supported on the shaft, a cam mounted on the gear and arranged to oscillate the lever in a horizontal plane, and a horizontal rotatable worm in mesh with the gear to drive the same.

3. A speed-reducing mechanism comprising a vertical shaft, an arm extending outwardly from the shaft, a one-way clutch mechanism connecting the arm with the shaft, an adjustable stop to limit the movement of the arm in one direction, a spring to move the arm toward the stop, a lever located beneath the arm and pivotally supported at one end about a vertical axis at one side of the shaft, the other end of the lever being arranged to engage the arm and move the arm in opposition to the spring, a worm gear rotatably supported on the shaft beneath the lever, a cam on the upper face of the gear and arranged to oscillate the lever about its pivotal axis, and a horizontal rotatable worm in mesh with the gear to drive the same, the worm being located on the opposite side of the shaft from the pivotal axis for the lever.

4. A speed-reducing mechanism comprising a vertical shaft, an arm extending outwardly from the shaft, a one-way clutch mechanism connecting the arm with the shaft, an adjustable stop to limit the movement of the arm in one direction, a spring to move the arm toward the stop, a lever located beneath the arm and pivotally supported at one end about a vertical axis at one side of the shaft, the lever having a transverse slot therein through which the shaft extends and the free end of the lever being arranged to engage the arm and move the arm in opposition to the spring, a pair of spaced parallel ribs extending longitudinally of the lever on the lower face thereof, a worm gear rotatably supported on the shaft beneath the lever, a circular cam eccentrically positioned on the upper face of the gear and located between the said parallel ribs, and a horizontal rotatable worm in mesh with the gear to drive the same.

5. A speed-reducing mechanism comprising a vertical shaft, an arm extending outwardly from the shaft, a one-way clutch mechanism connecting the arm with the shaft, a horizontal rotatable screw, a nut mounted on the screw and pro viding an adjustable stop to limit the movement of the arm in one direction, a spring to move the arm toward the stop, a lever located beneath the arm and pivotally supported at one end about a vertical axis at one side of the shaft, the free end of the lever being arranged to engage the arm and move the arm in opposition to the spring, a worm gear rotatably supported on the shaft below the lever, a cam on the upper face of the gear and arranged to oscillate the lever about its pivotal axis, and a horizontal worm in mesh with the gear to drive the same.

6. A speed-reducing mechanism comprising a vertical shaft, an arm extending outwardly from the shaft, a one-way clutch mechanism connecting the arm with the shaft, an adjustable stop to limit the movement of the arm in one direction, means to move the arm toward the stop, a pivotally mounted lever to move the arm in the opposite direction, a rotatable wheel coaxial with the shaft, a cam mounted on the wheel and arranged to oscillate the lever, and

means to rotate the wheel.

L. V. ANDREWS. 

